Similar to this question I am looking at connecting 1000's of concurrent users:
OpenVPN performance: how many concurrent clients are possible?
To save CPU cycles I would like to know if there is another solution outside of OpenVPN to bandwidth shape this many concurrent users?
From a performance perspective (OpenVPN offers more than just encryption), this is key
After further research, yes you can disable encryption in OpenVPN with these configuration directives:
auth none
cipher none
Set these in your server configuration and you will have no security at all provided by OpenVPN
See for example: http://docs.openvpn.net/under-the-hood/change-encryption-cipher-in-access-server/
In this answer an approach is shown to let OpenVPN run with multiple instances for better performance.
As mentioned in this forum post, OpenVPN could run into performance problems when the client count per instance exceeds 200 users, this is because of the monolithic way it was coded in. This will not change until version 3 as stated in the post.
